Interactive Form
I quite like this step-by-step interface for a form, all cleverly handled with the :focus pseudo-class. I’d want to refine some of the usability issues before using it in production, but the progressive disclosure is nice.
To-Do Terrarium
I love this little to-do app! Every time you tick something off your list, something grows in your virtual terrarium. Lovely!
Related links
Cooper Journal: One free interaction
Small interactions that serve no useful purpose but are nonetheless satisfying. "Design this interaction such that: It's “free,” i.e. having no significance to the task or content, It's discoverable in ordinary use of the product, It's quick and repeatable (Less than half a second.), It's pleasant"